Write this ratio in its simplest form:

2/9 : 9/2

Explain and show your workings.

The ratio can be simplified by dividing both the numerator and denominator of each fraction by their greatest common factor (GCF). The GCF of 2 and 9 is 1, so the ratio can be simplified to:

2/9 : 9/2 = 2/9 : 9/2 = 2/1 : 9/1 = 2 : 9

Therefore, the ratio in its simplest form is 2 : 9.